Device for checking whether each of running yarns is twisted at the standard turns per minute

ABSTRACT

The device of the present invention is used for checking whether each of running yarns is twisted at the standard turns per minute. This device comprises a driving shaft, a motor provided with a variable speed means and a yarn contact means. The driving shaft is rotated at a rotating speed corresponding to the standard turns per minute, at which each of running yarns should be twisted. The yarn contact means is imparted a torque from the shaft and running yarn, which is brought in contact with it. The shaft and the yarn contact means carry marks which can be viewed with a stroboscope to determine whether the shaft and contact means are rotating at the same speed.

United States Patent Hada June 6, 1972 [s41 DEVICE FOR CHECKING WHETHER [56] References Cited EACH 0F RUNNING YARNS IS TWISTED AT THE STANDARD TURNS UN'TED STATES PATENTS PER MINUTE 3,063,293 1 1/1962 Hutchens et al..

Inventor: Yultihiro Hada, Fujiyoshida, Japan Assignees: Unitika Ltd., Amarasaki-shi, Hyogo-ken;

Fujikeiki Kabushiki Kaisha, Fujiyoshidashi, Yamanashi-ken, Japan Filed: June 1, 1970 Appl. No.: 4|,9S9

Foreign Application Priority Data 3,377,853 4/1968 Carter ..73/160 Primary Examiner-Stan1ey N. Gilreath Assistant Examiner-Wemer H. Schroeder Attorney-Thomson & Mrose [57] ABSTRACT The device of the present invention is used for checking whether each of running yarns is twisted at the standard turns per minute. This device comprises a driving shaft, a motor provided with a variable speed means and a yarn contact means. The driving shaft is rotated at a rotating speed corresponding to the standard turns per minute, at which each of running yarns should be twisted. The yarn contact means is imparted a torque from the shaft and running yarn, which is brought in contact with it. The shaft and the yarn contact means carry marks which can be viewed with a stroboscope to determine whether the shaft and contact means are rotating at the same speed.

6 Claims, 5 Drawing Figures PATENTEDJUK 6 I972 SHEET 10F 3 Fig.

iNVENTOR YUK/H/RO HA DA ATTORNEYS ROTATION OF THE DRIVING SHAFT (RPM) ROTATION OF THE YARN CONTACT DISK (RPM) m INVENTOR YUKN/IAO NADA ATTORNEYS PATENTEDJUH 61972 3667292 SHEET 30F 3 INVENTOR YUK/H/PO HAD/j BY (1 1ml H'I J 5 f ATTORNEYS DEVICE FOR CHECKING WHETHER EACH OF RUNNING YARNS IS TWISTED AT THE STANDARD TURNS PER MINUTE BACKGROUND OF THE INVENTION This invention relates to a device for checking whether each of a number of running yarns is twisted at the standard turns per minute, and which is usable in conjunction with apparatus for imparting false twist to thermoplastic, organic yarn in order to impart crimp thereto.

It has been known in the art that the false twisting technique is used for imparting crimp to thermoplastic, organic yarn. In the process of producing the crimped yarn, it is customary to use apparatus in which a number of false twisting units is arranged in a group as one set. On the other hand, in all commercial fields where crimped yarns are used, a requirement is that all the yarn products produced by using such apparatus have the same crimp. For the purpose of such uniformity of the crimped yarn products, it is required that all the false twisting units in the false twisting apparatus twist all of the yarns at the same number of turns per minute. There are several types of false twisting apparatus for imparting crimp to the yarn, such as, for example, spindle type apparatus and friction type apparatus.

The spindle type has advantages in that the uniformity of crimp can readily be achieved between the products, because the speed of rotation of the spindle exactly controls the number of turns of the yarn per minute. Therefore, all of the yarns in this apparatus can be twisted at the same turns per minute by merely controlling the apparatus as to drive all of the spindles at the same speed of rotation. However, the spindle type apparatus is open to disadvantage of low production.

The friction type is capable of attaining higher production, but, has a disadvantage in that uniformity of the yarn products is difficult to achieve. In the case of the friction type apparatus, the torque by which the yarn is rotated depends entirely upon the frictional force occuring between the running yarn and the friction moving member, in frictional contact with which the yarn is disposed. However, it is difficult to determine exactly the amount of frictional force applied, particularly when the yarn and/or the friction moving member is moving at a high speed.

If the actual number of turns per minute of a running yarn being twisted by a frictional device can be detected, the twisting device can be adjusted in a known way to produce a desired standard number of turns per minute of twist. Thus each of a set of twisting devices can be adjusted to produce uniform twist, and therefore uniform crimp, in a group of yarns running through the devices.

The object of this invention is to provide a device for checking the actual number of turns per minute of twist being imparted to a running yarn in false twisting device in comparison to a desired standard number of turns per minute.

SUMMARY OF THE INVENTION The device comprises a driving shaft having a mark set thereon, a motor equipped with a speed regulating means and capable of driving said driving shaft at a speed of rotation which corresponds to the standard turns per minute of the yarn, and a yarn contact means having a mark set thereon and being a free running fit on said driving shah. A change in related position between the two marks indicate a discrepancy between the speed of the yarn contact means and that of the driving shaft.

The rotating speed of the yarn contact means may be compared to that of the driving shaft by viewing the marks with a commonly used stroboscope.

To practice the present invention, the yarn contact means may be either a disk or a belt. la the case where the belt is provided in the device, it runs over pulleys being a free running fit on the driving shaft. This type may be used where space lirnitations in the twisting apparatus would prevent the use of a disk.

The essential principle of the device of the present invention is that both of the driving shafi and yarn transmit their speeds of rotation to the yarn contact means which is a free running fit on the driving shaft so that the turns of the yarn per minute can be relatively checked by regulating the rotation of the driving shaft so as to obtain a synchronous rotation of the driving shaft and the yarn contact means.

The procedure to check whether each of the running is twisted at the standard turns per minute while the yarns are being subjected to the false twisting operation in the apparatus is as follows.

I. Selecting any one of the units in which the yarn is being subjected to the false twisting operation at the standard turns per minute.

2. Disposing the device between the heater and the friction moving member and bringing its yarn contact means in contact with the yarn so that the periphery edge of the means interrupts the imagenary plane in which the running yarn lies. The speed regulating means of the motor is then operated so as to change the speed of the driving shaft gradually until a synchronous speed of the driving shaft and the yarn contact means can be found. Having found the synchronous speed, it is thereafter kept as the speed which corresponds to the standard turns per minute of the yarn.

. Applying the device to another false twisting unit keeping the driving shaft at the same speed as that obtained in the above step. If any discrepancy of speed of the yarn contact means is viewed in comparison with the speed of the driving shaft, then the condition under which the yarn is false twisted should be corrected until the discrepancy disappears. It will be noted that when the discrepancy disappears and the rotation of the yarn contact means has synchronized with the rotation of the driving shaft, the yarn proves to be twisted at the standard turns per minute. This is carried out as to the other units.

The present invention will be explained more fully by way of embodiments, with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view illustrating an apparatus for producing the crimped yarn by false twist technique, to which the device of the invention is applied;

FIG. 2 is an explanatory graph showing the variation in rotation of the disk;

FIG. 3 is an elevation, partly in cross section of a modified form of the invention;

FIG. 4 is an elevation, partly in cross section of another modified form of the invention; and

FIG. 5 is an elevation, partly in cross section of still another modified form of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiment in FIG. I comprises a disk I fixed to the driving shaft 2 of the electric motor 3 while another disk 4, the yarn contact means, is a free running fit on the driving shaft 2 through ball baring 5 and tends to rotates in the direction in which the driving shaft rotates. Y advances yarn. Marks 6 and 7 are on the periphery edge surfaces of the disks l and 4 respectively so as to serve as an indicater when the speed of rotation of the disk 4 is viewed by means of a usual stroboscope in comparison with that of the disk I. Heater 8 and friction moving member 9 are the essential parts of the friction type of false twisting apparatus in which yarn Y advances from the let-off package (not shown) through the heater 8 to the friction moving member 9. In the internal space of the heater 8, there is provided an electric wire to heat the running yarn. The moving friction member 9 is rotated by any means not shown, in the direction indicated by the arrow. The yarn Y is passed diagonally from the left side, upper portion of the cylindrical member 9 in the drawing, through the inner bore of the member, and is withdrawn from the right side, lower portion of the same member 9. The yarn Y is rotated due to the frictional force of the member 9 and is imparted the false twist. Further, the yarn Y is subjected to the heat fixation by the heater 8 while in the twisted condition, and is then untwisted. The yarn is thus crimped.

The device of the invention is applied to the above described apparatus for checking whether each of the running yarns is being subjected to the false twisting operation at the standard turns per minute.

The disk 4 of the device is brought in frictional contact with the running yarn between the heater 8 and the member 9 with its periphery edge interrupting the imagenary plane in which lies the running yarn, said disk 4 having its axis disposed in parallel with the yarn Y. Before the disk is brought into engagement with the yarn, the driving shafi 2 is rotated at a speed estimated to be equal to that which is to synchronize with the speed of the disk 4 when the disk engages with the running yarn. The speed regulating means is then operated to change the speed of the driving shaft until a synchronous speed of rotation of the disk 4 and the driving shaft is found, while the periphery edge of the disk 4 is being kept in driven engagement with the running yarn. lt will be noted that the ball bearing will not in this operation offer any frictional resistance because the inner race, which is mounted on the driving shaft rotates with a linear speed close to a linear speed of the outer race of the ball bearing which is fixed to the disk 4, is the frictional resistance in the ball bearing 5 is negligible when thus running, every fluctuation of rotation of the yarn is transmitted exactly to the disk 4, through the driving engagement with disk 4, Thus, the actual rotation of the yarn is translated exactly into the increase or decrease of rotation of the disk 4 as compared with that of the driving shaft 2. This is the remarkable fleature of the invention which heretofore has not been obtained. In other words, the remarkable feature of the device is that the disk 4 compares the actual rotation of the yarn with the rotation of the driving shaft 2 and can translate every discrepancy into exactly the decrease or increase of speed of rotation of the disk 4 with minimum error due to friction. Any difference between the speed of rotation of disk 4 and that of shaft 2 can be detected by viewing marks 7 and 6 with a stroboscope of the type ordinarily used to measure high speed rotary motion.

Having found the above synchronous speed, it is thereafter kept as a standard speed of the driving shaft 2 with which the rotation of the disk 4 is compared for checking the false twisting units other than that in which the standard rotating speed was determined. The device is thus used for checking a second false twisting unit as to seeing whether the running yarn in the second unit is being twisted at the desired number of turns per minute.

in this operation, if there is viewed any discrepancy of the speed of the disk 4, then the condition under which the yarn is subjected to the false twisting operation should be changed until the synchronous speed of both disks 4 and 1 might be attained, while the rotation of the driving shaft 2 is being maintained at the same speed. it will be found that by gaining the synchronous speed in the second unit, the rotation of the yarn, i.e., the turns per minute of the yarn in the second unit proves to be the same as that of the yarn in the first unit in which the standard speed of the driving shaft 2 has been determined.

By repeating the above process as to all the remainder of the units, all of the units in the apparatus may be checked as to their condition under which the yarns are subjected to the false twisting operation.

EXAMPLE The device as shown in H6. 1 was used. The dimensions of the device were as follows.

Diameter of the disk 4 49.5 mm. Weight of the disk 4 4.0 gram Curvature of a portion of the periphery edge of the disk 4 I200 m.m. Ball bearing Internal diameter of the outer race 2.0 nun. Width of the race 2.5 mm. Rated load i700 Kgr.

Type of the ball bearing Radial ball bearing A polycaprolamide yarn (50 denier/l2 filaments) was twisted at a speed of 250 meter per minute on the standard false twisting unit of the apparatus. Note: The running yarn was partially cut-off between the heater and friction moving member. A twist of the sample yam obtained was 4,040 turns per meter. (This means that the yarn was twisted at 4,040 X 250 turns per minute) FIG. 2 shows the variation in speed of the disk 4 according to the example.

Line A represents the variation in speed of the motor or driving shaft and simultaneously represents the variation in speed of the disk 4 when out of engagement with the yarn while the line B represents the variation in speed where the yarn engages with the disk 4. It will be found from the graph that in case where there is no engagement of the yarn with the disk 4, the disk does not initiate its rotation until the speed of the driving shaft attains 1,300 revolutions per minute. However, it will also be seen from the graph that the disk 4 may be rotated by merely applying the torque from the rotating yarn at the speed of rotation of 1,700 revolution per minute even though there is no in-put torque from the driving shaft. Further, it will be seen that as the speed of the driving shaft increases, the speed of the disk 4 gradually increases along the curved line B, and when the speed attains to 2,550 revolutions per minute, the speed of the disk attains the same speed as in the case where there is no in-put torque from the yarn as shown by the point C in the drawing.

In case of a device in which the disk 4 is a free running tit on a stationary shaft, the speed of rotation of the disk does not vary exactly as the speed of rotation of the rotating yarn, par ticularly when the yarn is twisted at a high number of turns per minute.

In FIG. 3, there is shown a modification of the device of the invention, in which the disk 10 and motor 11 are similar to those of the embodiment in FIG. I and the disk 10 is fixed to the shaft 12. The lower end of the shaft 12 is supported by ball bearing 13, the upper end of the shaft 12 being supported by pivot bearing [4 which is in turn supported by ball bearing 15. The torque from the driving shaft 16 is transmitted to the disk 10 through the ball bearing 13 afixed at the top end of the driving shaft 16. It will be found that the modification is useful to hold the frictional resistance offered by the ball bearings within alower range than the embodiment of FIG. 1.

in H6. 4 there is shown another modification of the device in which the number of bearings arranged between the shafts 25 and 26 and the disk 18 is further increased in comparison with that of the embodiment of FIG. 3. By the increment, the frictional resistance offered by the bearings may be held within a range even lower than that of the other embodiments. The disk 18 is supported on the shaft 17 by ball bearing 20. Both ends of the shaft [7 are supported by pivot bearings 21 and 22 respectively. The pivot bearings 21 and 22 are each supported on one of their faces by their one face shafts 25 and 26 respectively, pulleys 27 and 28 being fixed on the shafts 25 and 26 respectively. Belts 29 and 30 run over pulleys 27 and 31 and pulleys 28 and 32 respectively. The pulleys 31 and 32 are respectively fixed to opposite ends of the driving shaft 33 of the motor 34.

in FIG. 5 there is shown still another modification. In this modification, a belt 35, which is the yarn contact means, runs over pulleys 36 and 37 which are supported on shafts 38 and 39 respectively through ball bearings 40 and 41. Shaft 39 is driven by the motor 42 The shaft 38 is rotated by the motor 42 through pulley 43, belt 44 and pulley 45. This modification is conveniently used for checking in a narrow space in the twisting apparatus.

All three modifications are used in essentially the same manner as the embodiment shown in FIG. 1.

lclaim:

1. A device, for checking the actual rate of twist of a running yarn in a false twisting device, as compared to a standard number of turns per minute, comprising: a motor, having a variable speed control capable of running said motor at a speed corresponding to said standard number of turns per minute; a drive shaft driven by said motor and carrying a mark; and a yarn contact device mounted in freely rotatable relationship with respect to said drive shaft, said contact device carrying a second mark, and said marks being viewable to indicate by change in their relative positions any discrepancy between the speeds of said drive shaft and yarn contact device.

2. A device as described in claim I, said yarn contact means comprising a disk having a peripheral edge adapted to engage said yarn, and said drive shaft carrying a ball bearing on which said disk is mounted.

3. A device as described in claim I, said yarn contact device comprising a belt adapted to frictionally engage said yarn, and said drive shaft carrying a pulley which drives said belt.

4. A device as described in claim 1, said motor carrying a first ball bearing and said shaft carrying a second ball bearing, the device including a second shaft mounted on said ball bearings, and said yarn contact device comprising a disk mounted on said second shafi.

5. A device as described in claim 1 having a pair of pulleys mounted on said drive shaft, the device including a pair of belts, one driven by each of said pulleys, a second pair of pulleys, one driven by each of said belts, a second and third shaft driven by said second pair of pulleys, a pair of ball bearings one mounted on each of said second and third shafts, a fourth shaft mounted on said ball bearings and carrying a third ball bearing, and said yam contact device comprising a disk mounted on said third ball bearing.

6. A device as described in claim 1 including a first pulley mounted on said drive shaft, a first belt driven by said first pulley, a second shaft mounted parallel to said drive shaft and carrying a second pulley driven by said first belt, a first and second ball bearing mounted respectively on said drive shaft and second shaft, a third and fourth pulley mounted respectively on said first and second bearings, and said yarn contact device comprising a second belt mounted on said third and fourth pulleys. 

1. A device, for checking the actual rate of twist of a running yarn in a false twisting device, as compared to a standard number of turns per minute, comprising: a motor, having a variable speed control capable of running said motor at a speed corresponding to said standard number of turns per minute; a drive shaft driven by said motor and carrying a mark; and a yarn contact device mounted in freely rotatable relationship with respect to said drive shaft, said contact device carrying a second mark, and said marks being viewable to indicate by change in their relative positions any discrepancy between the speeds of said drive shaft and yarn contact device.
 2. A device as described in claim 1, said yarn contact means comprising a disk having a peripheral edge adapted to engage said yarn, and said drive shaft carrying a ball bearing on which said disk is mounted.
 3. A device as described in claim 1, said yarn contact device comprising a belt adapted to frictionally engage said yarn, and said drive shaft carrying a pulley which drives said belt.
 4. A device as described in claim 1, said motor carrying a first ball bearing and said shaft carrying a second ball bearing, the device including a second shaft mounted on said ball bearings, and said yarn contact device comprising a disk mounted on said second shaft.
 5. A device as described in claim 1 having a pair of pulleys mounted on said drive shaft, the device including a pair of belts, one driven by each of said pulleys, a second pair of pulleys, one driven by each of said belts, a second and third shaft driven by said second pair of pulleys, a pair of ball bearings one mounted on each of said second and third shafts, a fourth shaft mounted on said ball bearings and carrying a third ball bearing, and said yarn contact device comprising a disk mounted on said third ball bearing.
 6. A device as described in claim 1 including a first pulley mounted on said drive shaft, a first belt driven by said first pulley, a second shaft mounted parallel to said drive shaft and carrying a second pulley driven by said first belt, a first and second ball bearing mounted respectively on said drive shaft and second shaft, a third and fourth pulley mounted respectively on said first and second bearings, and said yarn contact device comprising a second belt mounted on said third and fourth pulleys. 